Abstract: Magnetic fluids, its sealing mechanism, and its sealing characters are brief summarized. The types and components of sealing element, and classification and steps of sealing element designing are introduced. The effect of sealing element parameters on sealing performance, the selection principle of sealing element parameters are studied. In accordance with a concrete situation, a sealing element of one magnetic source and two magnetic poles is selected and researched. A 30 stages of sealing element is designed practically. The issues warranted careful consideration in the process of manufacture and installa-tion of sealing element are discussed.

Key words: Design, Magnetic fluid, Manufacture, Sealing element, Arc preheating, Dissimilar metals, Interface, Joint strength, Ultrasonic seam welding